Waterloo Bridge

Actually the second bridge to stand on the site, the current
Waterloo Bridge was completed in 1945, having earnt the
inauspicious honour of being the only river crossing in the capital
struck by German bombing during the Second World War. Due to the
lack of a male workforce during the war, the majority that worked
on the construction of Waterloo Bridge were female, earning it the
unofficial title of 'The Ladies Bridge'.

Again named after a famous historical British military victory,
Waterloo Bridge is seen as the foremost ground level location in
the capital for its views of the River Thames, being on a strategic
bend in the waterway, allowing for clean views to the Houses of
Parliament to the west, and St Paul's Cathedral to the east.

The bridge runs from The Strand on the north side, above
Victoria Embankment, over to the South Bank, terminating on a
roundabout that contains the BFI IMAX, the largest permanent cinema
screen in the United Kingdom. The BFI National Film Theatre, or
NFT, was built directly beneath the southern side of the bridge,
where it makes landfall.

Sherlock and John 'access the homeless network' on the northern
side, having jumped the railings on the Victoria Embankment. Their
meeting takes place directly beneath the bridge, in an elevated
seating area with the aforementioned clean view to Westminster.
However, the location for the scene was chosen for a reason, as in
reality you will frequently find the homeless sleeping rough here
early in the morning.

Episodes Waterloo Bridge has appeared in

The nearest Tube stations are Embankment [Circle, District,
Northern, Bakerloo], which requires you to walk east to Waterloo
Bridge, Temple [Circle, District] which requires you to walk west,
or Waterloo [Jubilee, Northern, Bakerloo] - follow the signs for
the BFI IMAX and turn left onto Waterloo Road, which connects
directly to the Bridge itself.